1. Field of the Invention
The invention generally relates to a sliding window assembly. More specifically, the invention relates to a siding window assembly for a vehicle.
2. Description of the Related Art
Sliding window assemblies for vehicles are known in the art. Generally, the sliding window assemblies are mounted to a flange of the vehicle. A typical sliding window assembly includes a first and a second fixed panel configured to be coupled to the vehicle. The first and the second fixed panels are spaced from each other and define an opening therebetween. A sliding panel is movable relative to the fixed panels between a closed position and an open position to modify a size of the opening.
Typically, the sliding window assembly includes an upper track and a lower track spaced from the upper track. Each of the tracks is attached to the fixed panels. The sliding panel is movable along the tracks between the open and closed positions. Each of the tracks includes an elongated member and a rail with the elongated member disposed about an exterior of the rail for coupling the rail to the fixed panels. An adhesive comprising polyurethane is applied to a periphery of the fixed panels and the elongated member to bond the sliding window assembly to the flange of the vehicle. The elongated member provides a bonding surface within the opening between the fixed panels.
Typically, the elongated member comprises a polyvinyl chloride (PVC) material. Due to environmental concerns, there is a desire in the automotive industry to move toward using other materials, such as a thermoplastic polyolefin (TPO) material instead of the PVC material. However, a bond between the adhesive and the TPO material is weaker that a bond strength between the adhesive and the PVC material. The weaker bond strength that results from using the TPO material can result in the elongated member breaking free from the flange of the vehicle. If the elongated member breaks free of the flange, the elongated member may rattle against the flange causing unwanted noise. Additionally, the rattling of the elongate member may lead to a weakening of the bond between the fixed panels and the flange resulting in the sliding window assembly breaking free from the flange and falling off the vehicle. An attempted solution to increase the bond between the adhesive and the TPO material has been to include a primer on the TPO material. However, the use of the primer adds time and cost to the manufacturing of the sliding window assembly. Additionally, the primer is not effective in increasing the bond strength between the adhesive and the TPO material to a required strength such as the bond strength formed directly between the adhesive and the PVC material. Therefore, there remains a need to provide an improved sliding window assembly.